1. Field of the Invention
The present invention relates to heat sink assemblies, and particularly to a heat sink assembly with a fastener which has an elastic element and wedges that enhance attachment of a heat sink to an electronic device.
2. Description of Prior Art
Developments in today""s highly information-intensive society have led to remarkable improvements in performances of electronic devices. During operation of many contemporary electronic devices such as central processing units (CPUs), large amounts of heat are produced. Such heat must be quickly removed from the electronic device, to prevent the system from becoming unstable or being damaged. Typically, a heat sink is attached to an outer surface of the device to remove heat therefrom. Various fasteners can be used to attach the heat sink to the device.
An example of a conventional heat sink fastener is disclosed in Taiwan Patent Application No. 87204504. As shown in FIG. 4, the fastener 1 integrally comprises a pressing portion 11, a pair of operating portions 12 extending from opposite ends of the pressing portion 11, and a pair of legs 13 respectively depending from the operating portions 12. Each leg 13 has a catch 131 formed at a bottom end thereof, for engaging in a corresponding aperture defined in a CPU seat. In use, the fastener 1 is placed across a heat sink. One of the catches 131 is engaged in one aperture. The operating portion 12 that is opposite to the engaged catch 131 is depressed, to cause the opposite catch 131 to engage in the other aperture. The heat sink is thus attached to an outer surface of the CPU.
Operation of the fastener 1 is inconvenient, because unduly large force must be exerted on the operation portion 12 opposite to the engaged catch 13. Furthermore, when the fastener 1 is mass-produced, variations in dimensions of the fasteners 1 inevitably exist. Frequently, this results in a discrepancy between dimensions of a fastener 1 and dimensions of the apertures of the CPU seat. The fastener 1 cannot effectively prevent the heat sink from moving relative to the CPU when the combined fastener 1, heat sink and CPU are subjected to vibration or shock during normal use. This adversely affects stability of the heat sink on the CPU, and leads to inefficient heat removal.
An improved means of securing a heat sink to a CPU which overcomes the above-mentioned problems is desired.
Accordingly, an object of the present invention is to provide a heat sink assembly with a fastener which can eliminate relative discrepancies in dimensions to enhance attachment of a heat sink to an electronic device.
Another object of the present invention is to provide a heat sink assembly having efficient heat removal capability.
To achieve the above-mentioned objects, a heat sink assembly of the present invention comprises a mother board, a CPU, a pair of retention modules, a heat sink and a fastener. The retention modules are secured to the mother board at opposite sides of the CPU. The heat s ink is attached to the CPU. The fastener comprises a spring, and a pair of wedges engaged at opposite ends of the spring. The fastener engagingly spans across the heat sink. The spring provides the fastener with resiliency, and presses the wedges against the retention modules. The wedges are pressed by the retention modules toward the CPU, thereby pressing the heat sink against the CPU.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.